> Do you agree or disagree that Mary constructing a red LED to experience redness is not a legitimate response to the Knowledge Argument?
It depends on what you think the Knowledge Argument is supposed to prove.
If you think the Knowledge Argument is supposed to prove that physicalism is false, then I disagree. To refute physicalism, it is pointless to say that some physical processes are not "knowledge". Even if the physicalist agrees, that in no way refutes physicalism. The physicalist simply says that the processes that Mary induces in her brain by constructing a red LED (or doing surgery on her optic nerve, or just imagining what seeing red would be like), even if they are not "knowledge", are still physical processes, and that those physical processes are Mary's experience of seeing red. Nothing in the Knowledge Argument refutes that.
If you think the Knowledge Argument is supposed to prove that there are physical things that aren't "knowledge" (whether or not there are also non physical things is then a separate question), then I neither agree nor disagree as a matter of physics, since what we use the word "knowledge" to refer to is a matter of definitions of words, not physics. I have no problem with accepting your definition of the word "knowledge" for purposes of this discussion. I just don't think accepting that definition says anything about whether or not physicalism is true.
> The physicalist simply says that the processes that Mary induces in her brain by constructing a red LED (or doing surgery on her optic nerve, or just imagining what seeing red would be like), even if they are not "knowledge", are still physical processes
This isn't relevant. Nobody is really disputing that physical processes cause qualia. You don't see the redness of an apple until the apple actually enters your visual field. Cause=physical event, result=qualia. Even dualists agree with this.
Therefore the Knowledge Argument is not about whether any physical process is causally linked to qualia, it's specifically about whether qualia can be deduced only from factual knowledge, because under physicalism, all facts are physical facts.
If physicalism is true, then all facts are third-party objective physical facts. Therefore quale are physical facts. If given an understanding of all physical facts, then Mary should be able to deduce her quale. If she cannot deduce her quale (or it seems very implausible), then either some mistake has been made or physicalism is false. Where is the mistake?
You cannot answer this question by saying her knowledge gives her the ability to trigger the usual physical process to cause qualia, because the question is about the deduction. The only outcomes of this thought experiment are one of: 1. denying that physicalism is true, or 2. denying that quale are facts, 3. accepting that Mary would be able to deduce her quale, 4. concluding that the thought experiment contains some inherent contradiction.
If Mary had (and had the capacity to conpletely analyze) all data on all physical processes in the universe, she could deduce her, and all other, qualia.
That Mary has all factual knowledge is a premise, the conclusion that she could deduce her qualia does not necessarily follow, and you have provided no proof demonstrating that it follows
> That Mary has all factual knowledge is a premise, the conclusion that she could deduce her qualia does not necessarily follow
It's not a conclusion; to a physicalist, it's part of the premise, since knowledge of her qualia is "factual knowledge". You can't just declare by fiat that this is false; that's a circular argument, as I have already said multiple times.
> you have provided no proof
The burden of proof is on you, not me; if you want to make an argument based on the claim that knowledge of qualia is not "factual knowledge", then you have to prove that it isn't. You can't just declare it by fiat.
I understand that non-physicalists, like you and Jackson, believe that knowledge of qualia is not "factual knowledge". But physicalists, like me and Dennett, disagree. Given that disagreement, you can't make your belief a premise of an argument and expect me to accept it. All you're doing is restating your position. Fine, I understand that's your position. But it's not the same as giving an actual argument for it based on premises that I must accept.
> The only outcomes of this thought experiment are one of: 1. denying that physicalism is true, or 2. denying that quale are facts, 3. accepting that Mary would be able to deduce her quale, 4. concluding that the thought experiment contains some inherent contradiction.
No, you left out one:
5. Denying that there is any difference, from the standpoint of testing whether physicalism is true or false, between Mary "deducing" her quale and Mary "triggering" her quale with a red LED or surgery or by imagining.
Basically you are trying to make an argument by redefining words to make arbitrary distinctions that don't have any bearing on whether physicalism is true or false. First you want to limit what Mary has to "knowledge", but nothing in physicalism requires all physical things to be "knowledge" or requires that all physical things must be reachable from "knowledge". Then you want to limit Mary to only having "factual knowledge", but nothing in physicalism requires all physical things to be "factual knowledge" or to be reachable from "factual knowledge". Then you want to limit Mary to only having "third-party objective physical facts", but nothing in physicalism requires that all physical things are "third-party objective physical facts". Then you want to limit Mary to only be able to "deduce" her quale instead of triggering it or imagining it, but nothing in physicalism requires someone to have to "deduce" their quale in order to know what it is like without having been subjected to the normal external stimulus (in this case the image of a red apple on Mary's retina) that would trigger it. Physicalism simply does not make or require any of these distinctions you keep making.
The claim of physicalism is simple: Mary's quale "seeing red" is a physical thing. (Or "process", or "fact", or whatever you want to call it; the substance of the claim remains the same.) The only way to disprove that would be to show that her quale being a physical thing somehow leads to a contradiction. The Knowledge Argument does not do that. It does not even claim to do that. It simply constructs a straw man version of "physicalism" that is vulnerable to refutation by this particular argument even though actual physicalism is not.
When you look at what physicalism actually says, the so-called Knowledge Argument boils down to a bare assertion. The premise is that Mary has all the physical information. The claim is that she learns something when she sees the red apple, implying that she did not have the information about what it would be like to see the apple beforehand, when she had all the physical information. But the claim simply does not follow from the premise; it is a non sequitur. The only way to get to the claim from the premise is to add an additional premise that having all the physical information does not include having the information about what it is like to see the red apple. But of course that is just arguing in a circle; it is simply assuming that physicalism is false in order to "prove" that physicalism is false.
The whole point of physicalism is that having all the physical information is having all the information, so it includes knowing what it is like to see red, to taste wine, to feel the sun shining on you, etc., etc., etc.. So any thought experiment that claims that Mary, who has all the physical information, will learn something when she sees the red apple is simply based on a false premise according to physicalism. Which makes it obvious that no such argument can refute physicalism.
> Basically you are trying to make an argument by redefining words to make arbitrary distinctions that don't have any bearing on whether physicalism is true or false.
No, this is a well studied problem by thousands of philosophers over 40 years. Maybe reconsider your position that you understand this argument better than they do. I don't see any benefit in continuing this discussion at this point.
> No, this is a well studied problem by thousands of philosophers over 40 years. Maybe reconsider your position that you understand this argument better than they do.
Ah, the old argument from authority. Sorry, not buying it.
> I don't see any benefit in continuing this discussion at this point.
It depends on what you think the Knowledge Argument is supposed to prove.
If you think the Knowledge Argument is supposed to prove that physicalism is false, then I disagree. To refute physicalism, it is pointless to say that some physical processes are not "knowledge". Even if the physicalist agrees, that in no way refutes physicalism. The physicalist simply says that the processes that Mary induces in her brain by constructing a red LED (or doing surgery on her optic nerve, or just imagining what seeing red would be like), even if they are not "knowledge", are still physical processes, and that those physical processes are Mary's experience of seeing red. Nothing in the Knowledge Argument refutes that.
If you think the Knowledge Argument is supposed to prove that there are physical things that aren't "knowledge" (whether or not there are also non physical things is then a separate question), then I neither agree nor disagree as a matter of physics, since what we use the word "knowledge" to refer to is a matter of definitions of words, not physics. I have no problem with accepting your definition of the word "knowledge" for purposes of this discussion. I just don't think accepting that definition says anything about whether or not physicalism is true.